Mortgage Calculator

How Mortgage Payments Work

A mortgage is an amortizing loan, which means each payment covers both interest and a portion of the principal. Early in the loan, the majority of each payment goes toward interest. Over time, as the outstanding balance shrinks, a larger share of each payment reduces the principal.

Your standard monthly payment is often called PITI: Principal, Interest, Taxes, and Insurance. Most lenders require property taxes and insurance to be paid into an escrow account alongside each mortgage payment, so the full PITI amount is what you actually write a check for each month.

If your down payment is below 20%, you will also typically pay Private Mortgage Insurance (PMI), which protects the lender — not you — in case of default. PMI can be cancelled once you reach 20% equity in the home.

Principal vs. Interest: The Amortization Shift

This is one of the most misunderstood aspects of mortgages. On a $400,000, 30-year loan at 6.8%, your monthly principal and interest payment is about $2,612. But in month one, roughly $2,267 of that goes to interest and only $345 goes toward the principal. By year 15, the split is closer to even. By year 25, principal dominates.

This is why making extra principal payments early in a mortgage has an outsized effect. Paying an extra $200/month from the beginning of a 30-year loan can shorten it by 5-7 years and save tens of thousands in interest.

Use the amortization table above to see exactly how your balance decreases year by year and when the interest-to-principal shift happens for your specific loan.

How to Get the Best Interest Rate

Your mortgage interest rate is largely determined by: your credit score, loan-to-value ratio (LTV), debt-to-income ratio (DTI), loan type, and current market conditions (driven by the Federal Reserve's benchmark rate and 10-year Treasury yields).

• •Improve your credit score. Moving from 680 to 740 can reduce your rate by 0.25-0.5%, saving thousands over the loan life.
• •Put down more. A larger down payment reduces your LTV and can unlock better rate tiers.
• •Shop multiple lenders. Getting quotes from at least 3-5 lenders (banks, credit unions, mortgage brokers) routinely saves $1,500-$3,000 over the life of a loan.
• •Buy points. Mortgage discount points let you pay upfront to lower your rate. One point costs 1% of the loan and typically reduces the rate by 0.25%.

15-Year vs. 30-Year Mortgage

This is one of the most consequential decisions a homebuyer makes. Here is the honest trade-off:

The 15-year saves over $284,000 in interest and builds equity much faster. But the $700/month higher payment must be sustainable. If you're choosing between the two, consider whether you could invest that $700 difference and whether your job security supports the higher obligation.

A useful middle path: take the 30-year for lower required payments, but pay it like a 15-year when possible. This gives you flexibility without locking in the higher payment.

Understanding PMI

Private Mortgage Insurance typically costs between 0.5% and 1.5% of the original loan amount annually, charged monthly. On a $320,000 loan, that is $133-$400 per month — real money for something that protects the lender, not you.

PMI is not permanent. Under the Homeowners Protection Act, you can request PMI cancellation when your loan balance reaches 80% of the original purchase price. The servicer must automatically cancel it at 78% LTV.

Ways to avoid PMI: put 20%+ down, use a piggyback loan (80-10-10), or look for lender-paid PMI programs (where a slightly higher rate replaces the separate PMI charge). Each option has trade-offs, so run the numbers for your situation.

Hidden Costs of Homeownership

The PITI payment is just the floor. Budget for these additional costs that catch many first-time buyers off guard:

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  Closing costs: 2-5% of the loan amount, paid upfront. On a $400,000 home with 20% down, expect $6,400-$16,000 at closing.
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  Maintenance and repairs: Budget 1-2% of home value annually. For a $400,000 home, that is $4,000-$8,000/year averaged over time.
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  HOA fees: Condos and planned communities often charge $200-$1,000/month in HOA dues — a significant recurring cost not reflected in the mortgage.
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  Utilities: Homeowners typically pay 20-40% more in utilities than renters due to larger spaces and responsibility for all services.
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  Property tax increases: Tax rates change. Model in a 2-3% annual increase in your long-term budget.